Cynthia Nixon, Amy Sedaris, Wanda Sykes and Julie White to appear in one of Amazon’s first original series

Amazon Studios is adding distaff appeal to the male-led cast of original series “Alpha House,” a political comedy written by “Doonesbury” creator Garry Trudeau.

Four thesps will guest star on the show, set to bow this fall on Amazon’s Prime Instant Video service: Cynthia Nixon (“Sex and the City”), Amy Sedaris (“Strangers with Candy”), Wanda Sykes (“Curb Your Enthusiasm,” “The New Adventures of Old Christine”) and Julie White (“Go On”).

“We’re lucky enough to have four of the most talented performers around joining the show,” Trudeau said in a statement. He previously worked with Nixon on HBO’s “Tanner ‘88″ political mockumentary miniseries.

On “Alpha House,” Nixon will play Sen. Carly Armiston, a formidable and confident Democratic senator from New York. She is joined by Sedaris, who will play Louise Laffer, the sweet, concerned wife of Sen. Louis Laffer (Malloy). Sykes is Sen. Rosalyn DuPeche, a strong-willed Democrat who happens to be a neighbor of the male senators, and White will play the tough-but-charming Southern wife of Goodman’s Sen. Gil John Biggs.

Amazon Studios, which the Internet retailer launched in 2010, is ramping up production of originals to take on Netflix, which has achieved buzz for series including “House of Cards” and “Orange Is the New Black.” Analysts say the Netflix original shows — a strategy that mimics that of premium cablers like HBO and Showtime — are already helping retain subscribers.

Part of Amazon’s strategy is an “open source” development process soliciting projects from anyone on the Internet; to date Amazon Studios has received more than 18,000 movie scripts and 4,000 series projects.